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#ifndef MS_RTC_RTP_PACKET_HPP
#define MS_RTC_RTP_PACKET_HPP
#include "common.hpp"
#include "FBS/rtpPacket.h"
#include "RTC/RTP/Codecs/DependencyDescriptor.hpp"
#include "RTC/RTP/Codecs/PayloadDescriptorHandler.hpp"
#include "RTC/RTP/HeaderExtensionIds.hpp"
#include "RTC/RtpDictionaries.hpp"
#include "RTC/Serializable.hpp"
#include "Utils.hpp"
#ifdef MS_RTC_LOGGER_RTP
#include "RTC/RtcLogger.hpp"
#endif
#include <flatbuffers/flatbuffers.h>
#include <array>
#include <map>
#include <string>
#include <vector>
namespace RTC
{
namespace RTP
{
/**
* RTP Packet.
*
* @see RFC 3550.
*/
class Packet : public Serializable, public Codecs::DependencyDescriptor::Listener
{
public:
/**
* RTP Fixed Header.
*
* @see RFC 3550.
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |V=2|P|X| CC |M| PT | sequence number |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | timestamp |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | synchronization source (SSRC) identifier |
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* | contributing source (CSRC) identifiers |
* | .... |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* @remarks
* - This struct is guaranteed to be aligned to 4 bytes.
*/
struct FixedHeader
{
#if defined(MS_LITTLE_ENDIAN)
uint8_t csrcCount : 4;
uint8_t extension : 1;
uint8_t padding : 1;
uint8_t version : 2;
uint8_t payloadType : 7;
uint8_t marker : 1;
#elif defined(MS_BIG_ENDIAN)
uint8_t version : 2;
uint8_t padding : 1;
uint8_t extension : 1;
uint8_t csrcCount : 4;
uint8_t marker : 1;
uint8_t payloadType : 7;
#endif
uint16_t sequenceNumber;
uint32_t timestamp;
uint32_t ssrc;
};
#ifdef MS_TEST
public:
#else
private:
#endif
/**
* RTP Header Extension.
*
* @see RFC 3350.
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | defined by profile | length |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | header extension |
* | .... |
*
* @remarks
* - This struct is guaranteed to be aligned to 2 bytes.
*/
struct HeaderExtension
{
/**
* Defined by profile.
*/
uint16_t id;
/**
* Number of 32-bit words in the extension, excluding the id & length
* four-octet.
*/
uint16_t len;
uint8_t value[];
};
public:
/**
* One-Byte and Two-Bytes Extension types.
*
* @see RFC 8285.
*/
enum class ExtensionsType : uint8_t
{
/**
* Auto means that One-Byte or Two-Bytes is choosen based on given
* extensions.
*/
Auto = 0,
OneByte = 1,
TwoBytes = 2
};
#ifdef MS_TEST
public:
#else
private:
#endif
/**
* @remarks
* - This struct is guaranteed to be aligned to 1 byte.
*/
struct OneByteExtension
{
#if defined(MS_LITTLE_ENDIAN)
uint8_t len : 4;
uint8_t id : 4;
#elif defined(MS_BIG_ENDIAN)
uint8_t id : 4;
uint8_t len : 4;
#endif
uint8_t value[];
};
#ifdef MS_TEST
public:
#else
private:
#endif
/**
* @remarks
* - This struct is guaranteed to be aligned to 1 byte.
*/
struct TwoBytesExtension
{
uint8_t id;
uint8_t len;
uint8_t value[];
};
public:
/**
* Struct for setting and replacing Extensions.
*
* @remarks
* - This struct is NOT guaranteed to be aligned to any fixed number of
* bytes because it contains a pointer, which is 4 or 8 bytes depending
* on the architecture. Anyway we never cast any buffer to this struct.
*/
struct Extension
{
Extension(RTC::RtpHeaderExtensionUri::Type type, uint8_t id, uint8_t len, uint8_t* value)
: type(type), id(id), len(len), value(value) {};
RTC::RtpHeaderExtensionUri::Type type;
uint8_t id;
uint8_t len;
uint8_t* value;
};
public:
/**
* Minimum size (in bytes) of the RTP Fixed Header (without CSRC fields).
*/
static const size_t FixedHeaderMinLength{ 12 };
/**
* Whether given buffer could be a valid RTP packet.
*
* @remarks
* - Before calling this static method, the caller should verify whether
* the given buffer is a RTCP packet.
*/
static bool IsRtp(const uint8_t* buffer, size_t bufferLength);
/**
* Parse a RTP packet.
*
* @remarks
* - `packetLength` must be the exact length of the packet.
* - `bufferLength` must be >= `packetLength`.
*
* @throw MediaSoupTypeError - If `bufferLength` is lower than
* `packetLength`.
*/
static Packet* Parse(const uint8_t* buffer, size_t packetLength, size_t bufferLength);
/**
* Parse a RTP packet.
*
* @remarks
* - `bufferLength` must be the exact length of the packet.
*/
static Packet* Parse(const uint8_t* buffer, size_t bufferLength);
/**
* Create a RTP packet.
*/
static Packet* Factory(uint8_t* buffer, size_t bufferLength);
/**
* Generate value for "urn:mediasoup:params:rtp-hdrext:packet-id"
* mediasoup custom extension.
*/
static uint32_t GetNextMediasoupPacketId();
private:
static thread_local uint32_t nextMediasoupPacketId;
private:
/**
* Constructor is private because we only want to create packet instances
* via Parse() and Factory().
*/
Packet(uint8_t* buffer, size_t bufferLength);
public:
~Packet() override;
void Dump(int indentation = 0) const final;
Packet* Clone(uint8_t* buffer, size_t bufferLength) const final;
flatbuffers::Offset<FBS::RtpPacket::Dump> FillBuffer(flatbuffers::FlatBufferBuilder& builder) const;
uint8_t GetVersion() const
{
return GetFixedHeaderPointer()->version;
}
uint8_t GetPayloadType() const
{
return GetFixedHeaderPointer()->payloadType;
}
void SetPayloadType(uint8_t payloadType);
bool HasMarker() const
{
return GetFixedHeaderPointer()->marker;
}
void SetMarker(bool marker);
uint16_t GetSequenceNumber() const
{
return ntohs(GetFixedHeaderPointer()->sequenceNumber);
}
void SetSequenceNumber(uint16_t seq);
uint32_t GetTimestamp() const
{
return ntohl(GetFixedHeaderPointer()->timestamp);
}
void SetTimestamp(uint32_t timestamp);
uint32_t GetSsrc() const
{
return ntohl(GetFixedHeaderPointer()->ssrc);
}
void SetSsrc(uint32_t ssrc);
bool HasCsrcs() const
{
return (GetFixedHeaderPointer()->csrcCount != 0);
}
bool HasHeaderExtension() const
{
return (GetFixedHeaderPointer()->extension);
}
/**
* Get the extension header id or 0 if there isn't.
*
* @remarks
* - This method doesn't validate whether there is indeed space for the
* announced header extension.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
*/
uint16_t GetHeaderExtensionId() const
{
if (!HasHeaderExtension())
{
return 0;
}
return ntohs(GetHeaderExtensionPointer()->id);
}
/**
* Pointer to the header extension value or `nullptr` if there is no
* header extension or its has no value.
*
* @remarks
* - This method doesn't validate whether there is indeed space for the
* announced header extension.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
*/
uint8_t* GetHeaderExtensionValue() const
{
auto headerExtensionValueLength = GetHeaderExtensionValueLength();
if (headerExtensionValueLength == 0)
{
return nullptr;
}
return GetHeaderExtensionPointer()->value;
}
/**
* Length of the header extension value (excluding the id & length
* four-octet).
*/
size_t GetHeaderExtensionValueLength() const
{
if (!HasHeaderExtension())
{
return 0;
}
return static_cast<size_t>(ntohs(GetHeaderExtensionPointer()->len) * 4);
}
/**
* Remove the header extension.
*/
void RemoveHeaderExtension();
/**
* Whether the packet has One-Byte or Two-Bytes extensions.
*
* @see RFC 8285.
*/
bool HasExtensions() const
{
return HasOneByteExtensions() || HasTwoBytesExtensions();
}
/**
* Whether the packet has One-Byte extensions.
*
* @see RFC 8285.
*/
bool HasOneByteExtensions() const
{
return GetHeaderExtensionId() == 0xBEDE;
}
/**
* Whether the packet has Two-Bytes extensions.
*
* @see RFC 8285.
*/
bool HasTwoBytesExtensions() const
{
return (GetHeaderExtensionId() & 0b1111111111110000) == 0b0001000000000000;
}
/**
* Whether the One-Byte or Two-Bytes extension with given `id` exists in
* the packet.
*
* @see RFC 8285.
*
* @remarks
* - If the length of the extension value is 0 this method returns `true`.
*/
bool HasExtension(uint8_t id) const
{
if (id == 0)
{
return false;
}
else if (HasOneByteExtensions())
{
if (id > 14)
{
return false;
}
// `-1` because we have 14 elements total 0..13 and `id` is in the
// range 1..14.
const auto offset = this->oneByteExtensions[id - 1];
return offset != -1;
}
else if (HasTwoBytesExtensions())
{
return this->twoBytesExtensions.find(id) != this->twoBytesExtensions.end();
}
else
{
return false;
}
}
/**
* Get a pointer to the value of the the One-Byte or Two-Bytes extension
* with given `id` and set its value length into given `len`.
*
* @see RFC 8285.
*/
uint8_t* GetExtensionValue(uint8_t id, uint8_t& len) const
{
len = 0;
if (id == 0)
{
len = 0;
return nullptr;
}
else if (HasOneByteExtensions())
{
if (id > 14)
{
len = 0;
return nullptr;
}
// `-1` because we have 14 elements total 0..13 and `id` is in the
// range 1..14.
const auto offset = this->oneByteExtensions[id - 1];
if (offset == -1)
{
len = 0;
return nullptr;
}
auto* extension = reinterpret_cast<OneByteExtension*>(GetHeaderExtensionValue() + offset);
// In One-Byte extensions value length 0 means 1.
len = extension->len + 1;
return extension->value;
}
else if (HasTwoBytesExtensions())
{
const auto it = this->twoBytesExtensions.find(id);
if (it == this->twoBytesExtensions.end())
{
len = 0;
return nullptr;
}
const auto offset = it->second;
auto* extension = reinterpret_cast<TwoBytesExtension*>(GetHeaderExtensionValue() + offset);
len = extension->len;
return extension->value;
}
else
{
len = 0;
return nullptr;
}
}
/**
* Add or replace extensions.
*
* @see RFC 8285.
*
* @throw MediaSoupTypeError - If there is no space available for given
* extensions or if given extensions are invalid/wrong.
*/
void SetExtensions(ExtensionsType type, const std::vector<Extension>& extensions);
/**
* Assign extension ids.
*
* @see RFC 8285.
*/
void AssignExtensionIds(RTP::HeaderExtensionIds& headerExtensionIds);
bool ReadMid(std::string& mid) const;
bool UpdateMid(const std::string& mid);
bool ReadRid(std::string& rid) const;
/**
* @remarks
* - `absSendTime` is set with the raw 3 bytes unsigned integer stored
* in the extension value.
*/
bool ReadAbsSendTime(uint32_t& absSendtime) const;
/**
* @remarks
* - Contrary to `ReadAbsSendTime()` method, given `ms` is internally
* converted to ABS Send Time.
*/
bool UpdateAbsSendTime(uint64_t ms) const;
bool ReadTransportWideCc01(uint16_t& wideSeqNumber) const;
bool UpdateTransportWideCc01(uint16_t wideSeqNumber) const;
bool ReadSsrcAudioLevel(uint8_t& volume, bool& voice) const;
bool ReadDependencyDescriptor(
std::unique_ptr<Codecs::DependencyDescriptor>& dependencyDescriptor,
std::unique_ptr<Codecs::DependencyDescriptor::TemplateDependencyStructure>&
templateDependencyStructure) const;
bool UpdateDependencyDescriptor(const uint8_t* data, size_t len);
bool ReadVideoOrientation(bool& camera, bool& flip, uint16_t& rotation) const;
bool ReadAbsCaptureTime(uint64_t& absCaptureTimestamp, int64_t& estimatedCaptureClockOffset) const;
bool ReadPlayoutDelay(uint16_t& minDelay, uint16_t& maxDelay) const;
bool ReadMediasoupPacketId(uint32_t& mediasoupPacketId) const;
/**
* Whether this packet has payload.
*
* @remarks
* - This method doesn't validate whether the padding length announced in
* the last byte of the packet is valid.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
*/
bool HasPayload() const
{
return GetPayloadLength() > 0;
}
/**
* Pointer to the beginning of the payload (if any). Payload length is
* set into given `length`.
*
* @remarks
* - This method doesn't validate whether the padding length announced in
* the last byte of the packet is valid.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
* - This method doens't take into account padding, so in a padding-only
* packet this method returns `nullptr` with `len` 0.
*/
uint8_t* GetPayload(size_t& len) const
{
auto* payloadPointer = GetPayloadPointer();
const size_t availablePayloadAndPaddingLength = GetLength() - (payloadPointer - GetBuffer());
const auto paddingLength = GetPaddingLength();
// If there is announced padding, compute effective payload length
// without padding.
if (availablePayloadAndPaddingLength > paddingLength)
{
len = availablePayloadAndPaddingLength - paddingLength;
return payloadPointer;
}
// If there are more announced padding bytes than the available length
// for payload and padding, assume payload length 0.
else
{
len = 0;
return nullptr;
}
}
/**
* Pointer to the beginning of the payload (if any).
*
* @remarks
* - This method doesn't validate whether the padding length announced in
* the last byte of the packet is valid.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
* - This method doens't take into account padding, so in a padding-only
* packet this method returns `nullptr`.
*/
uint8_t* GetPayload() const
{
thread_local size_t len;
return GetPayload(len);
}
/**
* Length of the payload excluding padding bytes.
*
* @remarks
* - This method doesn't validate whether the padding length announced in
* the last byte of the packet is valid.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
*/
size_t GetPayloadLength() const
{
const size_t availablePayloadAndPaddingLength =
GetLength() - (GetPayloadPointer() - GetBuffer());
const auto paddingLength = GetPaddingLength();
// If there is announced padding, compute effective payload length
// without padding.
if (availablePayloadAndPaddingLength >= paddingLength)
{
return availablePayloadAndPaddingLength - paddingLength;
}
// If there are more announced padding bytes than the available length
// for payload and padding, return 0.
else
{
return 0;
}
}
/**
* Set the payload. It copies the given `payload` into the packet.
*
* @remarks
* - This method removes existing padding (if any).
*
* @throw MediaSoupTypeError - If given `payloadLength` is higher than
* available length for the payload of if `nullptr` is given as
* `payload` with `payloadLength` higher than 0.
*/
void SetPayload(const uint8_t* payload, size_t payloadLength);
/**
* Set the payload length.
*
* @remarks
* - This method removes existing padding (if any).
*
* @throw MediaSoupTypeError - If given `payloadLength` is higher than
* available length for the payload.
*/
void SetPayloadLength(size_t payloadLength);
/**
* Remove the payload.
*
* @remarks
* - This method removes existing padding (if any).
*/
void RemovePayload()
{
SetPayload(nullptr, 0);
}
/**
* Shift or unshift the content of the payload `delta` bytes after
* `payloadOffset`.
*
* @remarks
* - This method removes existing padding (if any).
*
* @throw MediaSoupTypeError - If wrong values are given.
*/
void ShiftPayload(size_t payloadOffset, int32_t delta);
/**
* Whether this packet has padding.
*/
bool HasPadding() const
{
return (GetFixedHeaderPointer()->padding);
}
/**
* Length of the padding.
*
* @remarks
* - This method doesn't validate whether the padding length announced in
* the last byte of the packet is valid.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
*/
uint8_t GetPaddingLength() const
{
if (!HasPadding())
{
return 0;
}
return Utils::Byte::Get1Byte(GetBuffer(), GetLength() - 1);
}
/**
* Set padding length.
*
* @remarks
* - This method removes existing padding (if any).
*
* @throw MediaSoupTypeError - If given `paddingLength` is higher than
* available length for the padding.
*/
void SetPaddingLength(uint8_t paddingLength);
/**
* Whether packet length is padded to 4 bytes.
*/
bool IsPaddedTo4Bytes() const
{
return Utils::Byte::IsPaddedTo4Bytes(GetLength());
}
/**
* Pad packet length to 4 bytes by modifying padding bytes.
*
* @remarks
* - This method removes existing padding and adds up to 3 bytes of
* padding bytes if needed.
*
* @throw MediaSoupTypeError - If needed padding length is higher than
* available length for the padding.
*/
void PadTo4Bytes();
/**
* Encode the packet into a RTX packet.
*
* @remarks
* - This method removes existing padding (if any).
*
* @throw MediaSoupTypeError - If there is no space for the new computed
* payload.
*/
void RtxEncode(uint8_t payloadType, uint32_t ssrc, uint16_t seq);
/**
* Decode the RTX packet into a regular RTP packet.
*
* @return `true` if RTX decoding iwas done.
*
* @remarks
* - This method removes existing padding (if any).
*/
bool RtxDecode(uint8_t payloadType, uint32_t ssrc);
/**
* Set payload descritor handler.
*/
void SetPayloadDescriptorHandler(Codecs::PayloadDescriptorHandler* payloadDescriptorHandler);
/**
* Process the payload.
*/
bool ProcessPayload(Codecs::EncodingContext* context, bool& marker);
/**
* Get the payload encoder.
*/
std::unique_ptr<Codecs::PayloadDescriptor::Encoder> GetPayloadEncoder() const;
/**
* Encode the payload.
*/
void EncodePayload(Codecs::PayloadDescriptor::Encoder* encoder);
/**
* Restore the payload.
*/
void RestorePayload();
/**
* Whether the payload contains a video keyframe.
*/
bool IsKeyFrame() const
{
if (!this->payloadDescriptorHandler)
{
return false;
}
return this->payloadDescriptorHandler->IsKeyFrame();
}
/**
* Spatial layer of the video codec.
*/
uint8_t GetSpatialLayer() const
{
if (!this->payloadDescriptorHandler)
{
return 0u;
}
return this->payloadDescriptorHandler->GetSpatialLayer();
}
/**
* Temporal layer of the video codec.
*/
uint8_t GetTemporalLayer() const
{
if (!this->payloadDescriptorHandler)
{
return 0u;
}
return this->payloadDescriptorHandler->GetTemporalLayer();
}
private:
/**
* @remarks
* - Returns FixedHeader* instead of const FixedHeader* since we may want
* to modify its fields.
*/
FixedHeader* GetFixedHeaderPointer() const
{
return reinterpret_cast<FixedHeader*>(const_cast<uint8_t*>(GetBuffer()));
}
/**
* Pointer to the location where the CSRC list is supposed to begin.
*/
uint8_t* GetCsrcsPointer() const
{
return const_cast<uint8_t*>(GetBuffer()) + Packet::FixedHeaderMinLength;
}
/**
* Number of entries in the CSRC list.
*
* @remarks
* - This method doesn't validate whether there is indeed space for the
* announced CSRC list.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
*/
size_t GetCsrcCount() const
{
return GetFixedHeaderPointer()->csrcCount * sizeof(GetFixedHeaderPointer()->ssrc);
}
/**
* Pointer to the location where extension header is supposed to begin.
*/
HeaderExtension* GetHeaderExtensionPointer() const
{
return reinterpret_cast<HeaderExtension*>(GetCsrcsPointer() + GetCsrcCount());
}
/**
* Length of the header extension including the id & length four-octet.
*
* @remarks
* - This method doesn't validate whether there is indeed space for the
* announced header extension.
* - This method is guaranteed to return valid value once @ref Validate()
* was succesfully called.
*/
size_t GetHeaderExtensionLength() const
{
if (!HasHeaderExtension())
{
return 0;
}
return 4 + static_cast<size_t>(ntohs(GetHeaderExtensionPointer()->len) * 4);
}
/**
* Pointer to the location where the payload is supposed to begin.
*/
uint8_t* GetPayloadPointer() const
{
return reinterpret_cast<uint8_t*>(GetHeaderExtensionPointer()) + GetHeaderExtensionLength();
}
/**
* Validates whether the packet is valid. It also stores internal
* containers holding extensions if `storeExtensions` is `true`.
*/
#ifdef MS_TEST
public:
#endif
bool Validate(bool storeExtensions);
#ifdef MS_TEST
private:
#endif
/**
* Parses extensions. Returns `true` if they are valid. It also stores
* internal containers holding extensions if `storeExtensions` is `true`.
*
* @see RFC 8285.
*/
bool ParseExtensions(bool storeExtensions);
/**
* Set the value length of the extension with given `id`.
*
* @remarks
* - The caller is responsible of not setting a length higher than the
* available one (taking into account existing padding bytes).
* - If the extension with `id` doesn't exist this methods terminates
* the process.
*/
void SetExtensionLength(uint8_t id, uint8_t len);
/* Pure virtual methods inherited from Codecs::DependencyDescriptor::Listener. */
public:
void OnDependencyDescriptorUpdated(const uint8_t* data, size_t len) override;
#ifdef MS_RTC_LOGGER_RTP
public:
RtcLogger::RtpPacket logger;
#endif
private:
// Array of One Byte Extensions. Index is the id - 1 of the extension,
// each entry is the offset (in bytes) from the beginning of the header
// extension value to the beginning of the extension.
std::array<ssize_t, 14> oneByteExtensions{ -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1 };
// Ordered map of Two Bytes Extensions. Key is the id 1 of the extension,
// each entry is the offset (in bytes) from the beginning of the header
// extension value to the beginning of the extension.
std::map<uint8_t, ssize_t> twoBytesExtensions;
// Extension ids.
RTP::HeaderExtensionIds headerExtensionIds{};
// Codec related.
std::shared_ptr<Codecs::PayloadDescriptorHandler> payloadDescriptorHandler;
};
} // namespace RTP
} // namespace RTC
#endif